//--------------------------------------------------------------------------
//	Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
//  All rights reserved.
//
//	Redistribution and use in source and binary forms, with or without
//  modification, are permitted provided that the following conditions are
//  met:
//
//	Redistributions of source code must retain the above copyright notice,
//  this list of conditions and the following disclaimer.
//	Redistributions in binary form must reproduce the above copyright
//  notice, this list of conditions and the following disclaimer in the
//  documentation and/or other materials provided with the distribution.
//	Neither the name of the Drew Davidson nor the names of its contributors
//  may be used to endorse or promote products derived from this software
//  without specific prior written permission.
//
//	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
//  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
//  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
//  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
//  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
//  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
//  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
//  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
//  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
//  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
//  THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
//  DAMAGE.
//--------------------------------------------------------------------------
package ariba.util.expr;

import java.util.HashMap;
import java.util.Map;
import ariba.util.core.SecurityHelper;

/**
 * Default class resolution.  Uses Class.forName() to look up classes by name.
 * It also looks in the "java.lang" package if the class named does not give
 * a package specifier, allowing easier usage of these classes.
 * @author Luke Blanshard (blanshlu@netscape.net)
 * @author Drew Davidson (drew@ognl.org)
 */
public class DefaultClassResolver extends Object implements ClassResolver
{
    private Map     classes = new HashMap(101);

    public DefaultClassResolver()
    {
        super();
    }

	public Class classForName(String className, Map context) throws ClassNotFoundException
	{
	    Class       result = null;

        if ((result = (Class)classes.get(className)) == null) {
            if (!SecurityHelper.isScriptableClass(className)) {
                throw new ClassNotFoundException();
            }

    		try {
    		    result = Class.forName(className);
    		} catch (ClassNotFoundException ex) {
    			if (className.indexOf('.') == -1) {
                    String javaClassName = "java.lang."+className;
                    if (!SecurityHelper.isScriptableClass(javaClassName)) {
                        throw new ClassNotFoundException();
                    }
    			    result = Class.forName(javaClassName);
        			classes.put(javaClassName, result);
        		}
    		}
			classes.put(className, result);
    	}
	    return result;
	}
}
